Breadcrumb

1. Home

2. Print 

3. Pdf 

4. Node 

5. Entity Print 

NVAP Reference Guide: Johne’s

Disease (Control and Eradication)

Last Modified: 

Print

NVAP Reference Guide: Table of Contents

Questions, Comments, or Technical Issues?

NVAP Error Report Form

Preface

Introduction

Control and Eradication

Brucellosis

Johne’s Disease

Pseudorabies (PRV)

Tuberculosis

Transmissible Spongiform Encephalopathies

Scrapie

Bovine Spongiform Encephalopathy (BSE)

Chronic Wasting Disease (CWD)

Poultry
National Poultry Improvement Plan (NPIP)

Avian Influenza (AI)

Exotic Newcastle disease (END)

Equine Disease

Aquatic Animal

Aquatic Animal National Health Plan

Aquatic Animal Health Activities

Animal Health Emergency Management

Animal Health Emergency Management

Emergency Response Structure

National Response Framework (NRF)

National Incident Management System (NIMS)

National Animal Health Emergency Management System (NAHEMS)

Foreign Animal Disease Preparedness and Response Plan (FAD PReP)

FAD Recognition and Initial Response

National Animal Health Emergency Response Corps (NAHERC)

Notifiable Diseases and Conditions

WOAH and International Standards

Cleaning and Disinfection

Importance of Cleaning & Disinfection

Cleaning

Disinfection

Regulation of Disinfectants

Safety

Disease Surveillance

Laboratory Submissions

Animal Movement

Interstate Regulations

Interstate Movement of Cattle, Horses, Swine, Sheep and Goats

Issuing Interstate Animal Movement Documents

International Animal Movement

Issuing International Health Certificates (IHCs) for Live Animal Movement

Common Problems Observed on Certificates for Live Animal Movement
Animal Identification 

Animal Identification

Cattle Identification

Swine Identification

Equine Identification

Sheep and Goat Identification

Fowl Identification

Compliance and Regulations

Appendix

A: 9 CFR PARTS 160, 161, and 162

B: APHIS VS District Offices

C: State Animal Health Officials

D: Forms

E: Other Organizational Information with Contact Points

F: Web Sites

G: Equine Teeth and Aging

Johne’s disease is a contagious, chronic, and usually fatal infection that affects

primarily the small intestine of ruminants. Johne’s disease is caused by

Mycobacterium avium subspecies paratuberculosis (M. avium subsp.

paratuberculosis), a hardy bacterium related to the agents of leprosy and TB.

Johne’s disease is found worldwide.

Based on the 2007 Dairy NAHMS study, about 68 percent of U.S. dairy herds have at

least one cow that tests positive for Johne’s with herd prevalence approaching 100%

in large dairy herds. Because few herds have instituted biosecurity programs,

infection continues to spread. Although infection seems less widely distributed in

beef and goat herds and sheep flocks, Johne’s is nonetheless of critical significance

to all producers.

Johne’s disease can have severe economic impacts on infected herds. It is

imperative that U.S. herds and flocks employ safeguards against becoming infected.

Identifying and protecting noninfected herds and flocks will provide a source of

breeding stock and replacement animals for others and help to reduce the national
prevalence of the disease.

Clinical Signs and Stages

In cattle, signs of Johne’s disease include weight loss and diarrhea with normal

appetite. Several weeks after the onset of diarrhea, a soft swelling may occur under

the jaw. This intermandibular edema, or “bottle jaw,” is due to protein loss from the

bloodstream into the digestive tract. Animals at this stage of the disease will not live

very long—perhaps a few weeks at most.

Signs are rarely evident until 2 or more years after the initial infection, which usually

occurs shortly after birth. Animals exposed at an older age, or exposed to a very

small dose of bacteria at a young age, are not likely to develop clinical disease until

they are much older than 2 years.

In sheep and goats, the clinical sign are harder to spot. The intestines become thick

and less efficient at absorbing nutrients. Affected sheep continue to eat but lose

weight and “waste away.” Although the disease causes diarrhea in cattle, less than

20 percent of sheep show diarrhea. In up to 70 percent of sheep, the disease may

remain at subclinical levels, where individual animals never show signs of the

disease but shed the agent in their feces and infect other sheep and contaminate

the environment. In goats, weight loss, poor performance and occasionally clumpy

feces are all that is seen. Affected animals usually show sign before they are 1 year

of age.

Johne’s Disease is Generally Described as Having Four Stages

Stage I: Silent, subclinical, nondetectable infection

Typically, this stage occurs in calves, heifers, and young stock under 2 years of age

or animals exposed at an older age. Current tests (including fecal culture and

serological tests) cannot detect infection in animals that young. Research to develop

new tests to detect the disease in such animals is ongoing. This stage progresses

slowly over many months or years to Stage II. It is possible that some animals

recover from this early phase of infection.

Stage II: Subclinical shedders
This stage usually occurs in heifers or older animals. Animals appear healthy but are

shedding M. avium subsp. paratuberculosis in their manure at levels high enough to

be detected. Current blood tests are not reliable to detect Johne’s in animals at this

stage. These animals pose a major but often hidden threat of infection to other

animals through contamination of the environment. Stage II animals may or may not

progress over time to Stage III. 

Stage III: Clinical Johne’s disease

Animals in this stage have advanced infection, and clinical signs are often brought

on by stress. Clinical signs at this stage include acute or intermittent diarrhea,

weight loss despite a normal appetite, and decreased milk production. Some animals

appear to recover but often relapse in the next stressful period. Most of these

animals are shedding billions of Johne’s-causing organisms, and fecal organism

detection tests give positive results. Many animals are positive on serologic tests as

well. Clinical signs may last days to weeks before the animals progress to Stage IV.

Stage IV: Emaciated animals with fluid diarrhea

This is the terminal stage of the disease in which animals become extremely thin

and develop bottle jaw. Animals culled to slaughter in this stage may not pass

inspection for human consumption due to disseminated infection.

In the typical herd, for every animal in Stage IV, many other cattle are infected. For

every obvious case of Johne’s disease (Stage IV) among dairy cattle on the farm, 15

to 25 other animals are likely infected. The clinical case represents only the “tip of

the iceberg” of Johne’s infection.

In other ruminant species, the progression of the disease may occur more rapidly

with weight loss as the only visible sign of infection.

Epidemiology

Johne’s disease usually enters a herd when healthy but infected animals (Stage I or

II) are introduced. Cattle are most susceptible to the infection in the first year of life.

Calves most often become infected by swallowing small amounts of infected manure

from the calving environment or udder of the cow. In addition, calves can become

infected while in the uterus or by swallowing bacteria passed in milk and colostrum.
Studies have shown that up to 25 percent of calves are infected in utero if the cow is

in Stage III of the disease. Calves may become infected by exposure to

contaminated manure any time in the first year of life (e.g., from manure splatter to

calves raised near adult cows).  

Cattle of any age can become infected, though some age resistance does occur. This

age resistance can be overcome by high doses of bacteria over time from sources

such as manure-contaminated feed bunks or water sources. All ruminants are

susceptible to Johne’s disease. In addition, all infected animals shed the organism

through feces, thereby creating a possible route of exposure.  

Diagnosis

In the live animal, fecal organism detection tests (culture and polymerase chain

reaction methods (PCR)) are the most accurate diagnostic test. However, on a herd

basis only about 40 percent of infected cattle will be disclosed by even the most

sensitive fecal culture technique. The sensitivity of fecal culture is low because some

infected cattle (Stages I and II) do not shed the agent in their manure or because

some animals shed the agent only intermittently and can be missed at testing

time.  

In addition, M. avium subsp. paratuberculosis is a slow-growing organism. Fecal

culture on solid media requires 12 to 16 weeks for results. New liquid culture

systems have reduced this time to as little as 5 weeks. PCR methods can detect the

presence of M. avium subsp. paratuberculosis without its having to be grown. The

test has the advantage that it takes less than 3 days and may not be affected by

strain variations but has the disadvantages of higher cost and the potential of

missing animals shedding only low quantities of bacteria.  

Various serologic tests, including ELISA, agar-gel immunodiffusion (AGID), and

complement fixation, detect antibody in the serum and can be used on a herdwide

basis to screen for infection. Although less accurate than fecal culture, these tests

are more rapid and less expensive. Serologic tests also work well to confirm clinical

cases.  

It is important to note that, as an accredited veterinarian, you should use only the

USDA- licensed ELISA tests and USDA-approved laboratories. 
In the dead animal, Johne’s disease may be diagnosed by culture and histopathology

of the lower small intestine and associated lymph nodes.

Johne’s Disease Control Program

VS’ goal is to curtail the spread of M. avium subsp. paratuberculosis to noninfected

herds and to reduce the disease prevalence in herds currently infected. To

accomplish this goal, VS has developed a cooperative Federal–State–Industry

program that provides producer assistance by performing risk assessments for M.

avium subsp. paratuberculosis transmission and developing herd-management plans

to mitigate those risks.  

VS is also working to provide funding for research to develop and validate control

measures. Moreover, VS coordinates State activities and monitors current levels of

infection in the United States.

State Governments and Tribal Councils participate by providing personnel to conduct

risk assessments and aid in the development of herd-management plans. Depending

on funding available, these agencies also help producers by supporting testing at

reduced fees and underwriting other direct program costs. Industry cooperates by

encouraging producers to participate in the program through information provided in

industry journals and consultation with APHIS and professional societies. 

To work with the Johne’s Disease Control Program as an accredited veterinarian, one

must first become a Johne’s Certified Veterinarian. Johne’s Certified Veterinarians

have received additional education on the disease and have demonstrated to the

State-Designated Johne’s Coordinator that they can

1. Develop approved herd-management plans; 

2. Provide appropriate Johne’s disease risk assessments; 

3. Understand Johne’s disease epidemiology, testing, and test interpretation;

4. Understand State and Federal program requirements; and 

5. Collect and submit fecal, tissue, and blood samples for Johne’s disease testing. 

Johne’s Certified Veterinarians must provide Johne’s risk assessments and develop

herd- management plans and collect and submit samples according to the program

requirements. 
For information on Johne’s Certified Veterinarian training in your state, please

contact your State animal health official or your APHIS –VS Area Offices.

For further information on the Voluntary Bovine Johne’s Disease Control Program,

please go to: Johne's Disease Information

Prevention

For herds that are not infected, managers should take precautions against

introduction of Johne’s disease. Such precautions include keeping a closed herd or

requiring that replacement animals come from test-negative herds. Some States

offer Johne’s certification to test-negative herds. The new Uniform Program

Standards for the Voluntary Bovine Johne’s Disease Control Program (APHIS

91–45–014) outline a new, voluntary national Johne’s classification program that

helps to identify risk of infection in participating herds.

The Johne’s Program Standards can be found on the Web at: Johne's Program

Standards

The key to preventing Johne’s infection is to know that 

Herds get infected only when infected animals are added to the premises;

Prepurchase testing for Johne’s disease is today’s standard of veterinary

practice; and

Testing the herd of origin is much more reliable than testing only the purchased

animals.

Table 2 outlines options (in order of decreasing risk) of buying M. avium subsp.

paratuberculosis-infected animals. 

Options Risk

No testing.

Very risky—>5% percent chance, for

each purchased animal of being infected

with M. paratuberculosis

ELISA-test the individual animal before

purchase; do not purchase anything from

herds with cows positive by ELISA

Slightly less risky than not testing; more

confidence in negative tests on older

animals than heifers

Quarantine and test after purchase:

ELISA + culture twice at 6-month

intervals

Lowers risk and is sound policy for

several infectious diseases of cattle
Options Risk

Partial test on herd of origin: ELISA on 30

2

nd lactation or older cows

Low risk of Johne’s disease in any animal

from such herds but not 0%

Whole-herd ELISA or fecal culture on the

herd of origin.

Very low risk of Johne’s disease if herd

tests 100% ELISA-negative or culturenegative

Purchase only from test-negative status

herds (level 2 or higher)

Lowest possible risk for purchase of M.

paratuberculosis-infected herd

replacements